- At the edges of the valley, waterfalls (hanging valleys) flow down into the valley. - Anemometer An instrument for measuring the speed of the wind. - This shift is a result of the revolution of the earth around the sun.. - A geosyncline lifts up to form mountains because of the intense heat deep in the mantle. - Erosion of the softer rocks underneath undercuts the caprock.. - Celestial equator The projection of the earth's equator onto the celestial sphere. - In the case of the earth in orbit around the sun, the centripetal force acting on the earth is the sun's gravity. - The relative ages of the fossils can be determined by their positions in the layers. - The rocks are classified according to the size of the particles. - This happens frequently, at all times of the year. - Thunderstorms are formed in the very tall, violent clouds of the kind called cumulonimbus (See Thunderstorm).. - Hard coal, anthracite, is the final result of the process. - Constructional forces Forces in the earth's interior that produce deformations of the crust. - Differential heating of the ocean results in the massive movement of water. - Cretaceous period The final period of the Mesozoic era. - As the water evaporates, it cools the bulb of the thermometer. - The dinosaurs died out at the end of the Mesozoic.. - It is determined primarily by the nature of the underlying bedrock. - The materials of the earth are arranged in layers according to density. - The light gets to the moon by reflecting from the surface of the earth.. - Earth's interior The central zone of the earth. - Earthquake waves reveal the structure of the earth's interior. - Ecliptic The path of the sun across the celestial sphere. - The following are some of the important elements of the earth:. - of the hydrosphere. - Iron is the main component of the earth's core and is also present in the crust. - Thus, speed is a measure of the energy of the system.. - Equatorial countercurrent A large water current flowing eastward in the center of the Pacific Ocean.. - The moon's gravity produces tides and distortions of the earth's crust. - temperature of the earth increases. - What happens next depends on the mass of the star. - Hydrogen makes up about 75% of the universe. - The near side of the valley is extremely steep. - The energy of the sun comes to the earth in the form of electromagnetic waves, and about half is infrared. - About half of the earth's insolation is in the infrared, the rest is visible and ultraviolet. - Much of the incident radiation does not warm the earth because it is reflected. - Resolution depends on the size of the receiving antenna. - Interstellar medium The material in the vast, empty spaces of the universe. - In the earth's atmosphere, the ultraviolet rays of the sun ionize the air at a high altitude. - It is based on the granitic nature of the main mass of continental rock. - The satellite Io is one of the oddest bodies in the solar system. - In windstorms, it is the kinetic energy of the air that does damage. - The surface of the moon is pitted with craters. - This is a very small part of the whole spectrum. - It is determined chiefly by the wavelength of the light. - A lunar eclipse is partial when the earth's shadow covers only part of the moon. - Total eclipses of the moon occur, on the average, about once a year.. - It forms the upper layer of the earth's mantle. - Apparent magnitude is the apparent brightness of the stars. - Pressure is measured by the height of the mercury in the tube above the open surface. - The sun is a star in one of the spiral arms. - The center of the galaxy is obscured by dust.. - A few minerals make up the largest part of the earth's crust. - Moho The Mohorovicic discontinuity, the boundary between the crust and the mantle of the earth. - Nitrogen A gaseous element, making up 78% of the earth's atmosphere.. - North magnetic pole The S pole of the earth's magnetic field. - Ocean The saltwater mass that covers 72% of the earth's surface. - constitute ordinary salt, about 85% of the mineral matter in the sea. - Most of the rest is sulfate (SO 3 2-. - Great mountain ridges mark many parts of the ocean floor. - The shape of the orbit, in general, is an ellipse. - The partial pressure of the water vapor in the air is known as vapor pressure. - Perigee The point in the orbit of the moon or an earth satellite at which it is closest to the earth.. - Phylum Any of the main divisions of the animal kingdom (for example, Mollusca, Arthropoda).. - regardless of the size of the particles. - Precambrian Roughly, the first 4 billion years of the earth's history. - Temperature also determines the wavelength of the radiation emitted. - At still higher temperatures, much of the energy is in the ultraviolet. - Recharge Replenishment of the water table by precipitation. - Rock Solid matter making up the crust of the earth. - Seafloor topography The form of the bottom of the sea. - The decreasing insolation angle brings cooling of the weather. - Seismograph An instrument for measuring the vibrations in the crust of the earth. - Sialic rocks make up the core of the continents. - Humus generates acid, which contributes to the weathering of the rock.. - As weathering of the bedrock continues, all the layers deepen. - See Phases of the moon.. - flowing out of the sun. - The reason is the precession of the earth's rotation. - South of the Antarctic Circle, there is no daylight.. - The path is the result of the earth's rotation so it is circular. - Most of the star is hydrogen. - What happens next depends on the size of the star. - The subsequent history of the star depends on the mass remaining. - the hills are far away at the edge of the floodplain. - A large part of the star is blown off into space. - Tectonic plates The large, continent-sized pieces of the earth's crust. - The sudden heating of the air produces the thunder.. - At the time of the new moon the sun and the moon are on the same side of the earth. - Conventional time is measured by the rotation of the earth. - Local time is based on the length of the day.. - It is an important part of the atmospheric water cycle. - the wave velocity is along the length of the string.. - When it is on the other side of the sun from us, it is full. - The ash sometimes spreads very widely over distant parts of the earth. - It is a reflection of the climate. - Storage is the water in the zone of aeration of the soil, where it is accessible to plants. - Artesian wells even provide water to oases in the middle of the Sahara Desert. - Water table The upper surface of the zone of saturation. - It is determined by the amplitude of the vibration that produced the wave